2 second to black - LG monitor FLATRON W1934s-BN

[georgealbertwadie]

hi ,

i have a monitor as LG Flatron and it goes off after 2 seconds and i can see what is going on the screen but it is so dark . it goes off after 2
seconds i opened the monitor and i changed some capacitors but still goes off
(i changed the capacitors with blue color) and i checked almost all diodes on power board the seem ok . i attached 4 images for this problem .

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

i was testing the CCFL by making permutations(first connector to first then first to second and so on) when testing the lower lamps and switched on the the monitor i found fire in the transformer from beneath so i fastly switched off the monitor and removed the transformer..and powered on the monitor with one transformer .the screen lits on for 2 seconds and goes off. please need illumination .thanks

[budm]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

You need to have both working transformers otherwise the protection circuit will turn on, same for the lamps, all the lamps must be OK, one bad lamp or not connected lamp will alos cause the circuit to go into shutdown.

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

thanks for illumination , but i have another question when i unsoldered the two trnaformers T501 , T502

as i attached the image i write the measurements with the multimeter
i found a great difference in the resistance of the secondary side for both . which of them is defective ? or they are both defective

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

i was mistaken in the resistance of T502 the resistance on the secondary is
0.6 kilo ohm not 0.6 ohm since the range of the multimeter was on 2kohm

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

i thought that there is good support in this forum ?

[Ramee]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

Buying those are more expensive than buying the whole circuit board. They are both shorted.

[Rtech]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

1.6 KΩ is far to high and is faulty.This is probably the one that got hot.You neeed two working transformers to drive all the lamps.

[Ramee]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

i thought that there is good support in this forum ?

Post your circuit board here so i can see the part number on board, i will search for you where to buy, i think it's around 50USD more or less.

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

thank you for your illuminations , but iam asking if i can get around this
by using a subsistution by using this inverter board it has 3 cables connected to it i bought it from local market here in my country
it is written on it AVT1906 i don not know if this code is significant

the inverter board has 3 cables
Vin-GnD-ADJ

the inverter IC is DF6109a the data sheet in chinese
and the duo mosfet IC is : DTM4606

thanks to all who answered

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

@Ramee: please check the attached images.

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

hi ,this is a serial number on the power board of the LG1934 .thanks

[Ramee]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

I think this is your board, part number ILPI-071, check carefully. 23USD on sale, after 4 days, price will climb up to 26USD free shipping.

http://www.aliexpress.com/item/SUPER...578824064.html

[Ramee]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

If you have spare screen panel, you can swap it quick, before buying the power board.

[budm]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

Need more info about the inverter board you bought, we need to find out if the ADJ requires analog 0~5V for brightness adjustment or it needs PWM type signal.
It also should have ON/OFF control pin otherwise the backlights will be on all the time.
BTW, do not put the old transformers back on the board.

i thought that there is good support in this forum ?

Yes we do have good support in this site but you have to give us times, you are getting free advice here and we do have jobs beside helping out people here for free.
BTW, the reason the transformer winding burnt up can be due to bad lamps that drawing too much current.

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

thank u budm ,Ramee for your response , i really appreciate your support and response . thank u
the generic inverter has the following labels
(6) gnd-Gnd-ADJ-On-Vin-Vin (1) i really missed the on connector
and i have 2 questions
1-where to connect the ON connector ?
2-how to know the brightness is PWM control or Analog?

[budm]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

If you look at the power supply inverter board, there are labels for the connector that goes to the main board which tells you the function of each pin.
So post what they are.

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

hi budm, please check the attached image

[georgealbertwadie]

Re: 2 second to black - LG monitor FLATRON W1934s-BN

also i have attached the service manual